JPS59140234A - Sponge-like water absorbent - Google Patents

Abstract

PURPOSE:A sponge-like water absorbent into the entire volume of which water can permeate sufficiently and which has a large water retention, prepared by adding a highly water-absorptive resin to an open-cellular porous substance. CONSTITUTION:A sponge-like water absorbent is formed by the following methods, for example. Bread is immersed in a solution prepared by mixing (i) a highly water-absorptive resin powder (e.g., one prepared by graft-polymerizing acryl groups with starch) with an adhesive and an organic solvent to attach said resin powder to the inside walls of the cells in the bread, or (ii) flour is mixed with a highly water-absorptive resin powder and the mixture is baked into bread with the aid of yeast, baking powder, or the like. The above examples are those wherein bread based on flour is used as a porous substance. Polyurethane foam, sponge, diatomaceous earth, etc., may be used as said porous substance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sponge-like absorbent material in which a super absorbent resin is added to a porous material having open cells inside.

In recent years, acrylonitrile, acrylamide,
BACKGROUND ART Super absorbent resins called hydrogels, which are made by graft polymerizing polymers such as acrylic acid, have been developed, and their applications are being carried out in various ways. In its application, superabsorbent resin powder is sandwiched between fibers, pulp, or absorbent paper, and superabsorbent sheets are wrapped in the form of laminated products to be used for sanitary products, disposable diapers, gardening, water retention for seedlings, etc. There are methods such as putting it in a polymeric bag and using it for emergencies, and it has a much greater water absorption effect than conventional single products such as fibers and paper. However, although the superabsorbent sheet has a somewhat thick water-retaining area, it is flat and has a small amount of water retention, which limits its application even when supplemented with other papers, fibers, etc. In addition, when used in powder form, water is introduced only to a small area or part of the polymer bag that envelops the entire body, so water that has spilled on a flat surface may be sucked up or seeped in from an uncertain location. Although it can be effective in absorbing unpredictable liquids, its range of use is extremely limited.

Except for the above-mentioned limitations, the super absorbent sponge of the present invention has
In order to expand the range of applications, a super absorbent resin is added to a porous material with open cells inside, and the pore size, porous base material, particle size and proportion of the super absorbent resin powder are appropriately selected. This allows water to penetrate into the entire volume. Porous materials include polymeric foam products such as rubber sponge, polyethylene foam, polypropylene foam, and urethane foam, foods made of grain flour such as bread, cake, and castella cakes, living materials such as sponges and loofahs, and inorganic powders such as diatomaceous earth. There are many foamed products using inorganic materials such as pumice, porous ceramic, and phosphor, but any material can be used as long as it has open cells of an appropriate pore size and is not water repellent. In addition, materials are selected based on the purpose of use, safety to the human body, and non-polluting properties when disposed of. The present invention will be described in detail using bread made from wheat flour as an example that satisfies these conditions. In this case, there are two ways to add the super absorbent resin.

(1) A method in which bread is immersed in a liquid mixture of super absorbent resin powder, which is made by graft polymerizing acrylic groups onto starch, along with an organic solvent and an adhesive, so that it adheres to the inner walls of the air bubbles of the bread. (2) Flour A method of mixing the above super absorbent resin powder and baking bread using mystobacterium, baking powder, etc. In the case of (1), the organic solvent includes alcohols, ketones,
Esters, phenols, ethers, nitrogen compounds,
Although it contains sulfur compounds, it satisfies the requirements of containing as much water as possible, drying quickly, and not damaging the flour base material, and also selecting an appropriate solvent depending on the type of adhesive. Adhesives include natural adhesives, inorganic adhesives, and polymeric adhesives such as thermoplastic adhesives, thermosetting adhesives, and rubber adhesives, but this is related to the selection of solvent, and if it contains moisture, it will dry out. Since it is expensive, it is desirable that it does not contain water, has good adhesion to wheat flour, and is inexpensive to produce.

In the case of method (2), superabsorbent resin powder is added to a kneaded mixture of flour, water, and sugar that has undergone primary fermentation in advance, and
Perform baking. It is also possible to bake by adding so-called baking powder, which is a mixture of a gas-generating base material such as sodium hydrogen carbonate and a gas-generating promoter such as acidic calcium phosphate, instead of yeast. In either case, additives such as preservatives, antifungal agents, and antiaging agents may be used.

The water absorption capacity of the super absorbent resin powder-added bread obtained as described above is closely related to the size of the air bubbles, the amount of the super absorbent resin powder, and the particle size. That is, if the bubble pore diameter is small, the water absorbed by the highly water-absorbent powder added to the inner wall of the pore near the surface becomes gel-like, so that no water can pass inside. Furthermore, if the pore size is too large, water cannot be expected to penetrate through capillary action. The water absorption rate of highly water-absorbent powder made by graft polymerizing acrylic groups to starch is 80-100% of the total water absorption in 2-3 minutes.
The faster the sponge absorbs water, the more the cross-linked complex due to graft polymerization of starch molecules swells around the water, so in the end all the bubbles inside the sponge are filled with gelled water. However, in order to prevent the outside from gelling before the water penetrates into the inside, the pore size of the bubbles and the base material are adjusted so that the water absorption rate due to capillary action is faster than the gelation rate of the super absorbent powder. It is necessary to appropriately adjust the material (hydrophilicity), the particle size of the superabsorbent resin powder, and the amount added. When using bread, commercially available breads are difficult to satisfy these conditions and vary widely. Therefore, method (2) is preferable in terms of application, and the conditions can be adjusted freely. In the case of bread, the pore size is large near the center, and the pore size near the outer layer is small. Therefore, if you divide a large block into two parts and design a design that allows water to enter from near the center, and cover the entire surface area, the whole becomes one water-absorbing bag, and the pores near the center are large, allowing water to pass through to the surface area. Due to the hydrophilic nature of flour starch, the water penetration rate is fast, and the water absorption efficiency is 100%.
It can be adjusted close to %. The user can create one such block.
It can be used for emergencies, home gardening, etc., or it can be cut into thin slices and used for disposable diapers, children's underwear to prevent urine and urine, and general moisture-proofing purposes.

Although the above description has been made regarding wheat flour bread, the invention can be similarly applied to other grain flours such as rice flour, cornstarch, and potato flour.

When using a hexagonal polymer material as a porous material, the method is basically the same, and there are two methods as follows.

(1) Method of immersing in a solution (including solvent and adhesive) containing super absorbent resin powder after foam molding (2) Method of mixing super absorbent resin powder into the base material and foam molding method Polyurethane foam is an example. For bread, method (1) can be carried out in the same way as for bread. In the case of method (2), since the blowing agent for the urethane foam is water, it is preferable to disperse the superabsorbent resin powder in the incyanate solution 1 serving as the base material. In the case of urethane foam,
Since the gas generated during molding is carbon dioxide scum, it forms open cells and has good hydrophilicity, so it is suitable for application of the present invention. still,
In the case of urethane foam as well, there are appropriate values for the pore size of the bubbles and the amount of superabsorbent resin powder added, and by optimizing them, it is possible to retain water with an efficiency of about 90%. The present invention can be similarly applied to synthetic polymer foams other than urethane foam, and any foam material with open cells can be sufficiently put to practical use. In the case of bread and urethane foam, (2)
When foam molding is performed using the method described above, a small amount of water may remain in the bubbles (retained water in the superabsorbent resin powder), but in order to remove this, treatment such as heating vacuum dehydration may be performed. .

When using living organisms such as sponges and loofahs as porous material base materials, it is only necessary to use materials with air bubbles already formed.
Only method (1) above is possible. Even in the case of porous inorganic materials such as diatoms, the sintering temperature is usually high and method (2) destroys the structure of the superabsorbent powder, making it impossible to add an additional field to conventional planar fibers, pulp, etc. In comparison, its water retention capacity has been greatly improved. For example, when the present invention is applied to urethane foam and the conventional pulp or the like to which superabsorbent resin powder is added are compared, the results are as follows.

Material Powder addition amount Water absorption (city water) Water absorption capacity 120g/rrP 4. QQQc
c/m' 33cc/g urethane foam
50g/12z 9,600cc/121 192c
c/g, and the super absorbent resin powder is Me-Soushu 14
Use a fine powder of 5 or less, and the last number is the amount of water retained by 1 g of added super absorbent resin powder. -1 for powder alone
It has the ability to hold more than 400 Lc of city water per gram, and this ability is not fully utilized in conventional pulps. The liquid holding ability of super absorbent resin powder varies depending on the type of Z liquid and is degraded by impurities. Therefore, when it is applied as a product, it is preferable to add more than the above amount in consideration of the safety factor.

The effects of the present invention over conventional products are as follows.

(1) Compared to conventional products made by adding super absorbent resin to pulp, etc., the water absorption effect is improved several times.

(2) Compared to powder packed in a polymer bag, the water supply range is wider, so the range of applications is wider.

(3) The sponge according to the present invention can be freely used alone or cut into pieces, and the cost borne by the user is very low.

Example 1 Highly absorbent bread was prepared by adjusting raw materials in the following proportions.

Wheat flour 300 parts Water 165 copies Yeast 6 parts Super absorbent resin powder 15 parts Sand　　　　　　　　　　　　　　　4 parts The creation procedure is as follows.

First, mix some water, sugar and yeast, and temperature 30
Prefermentation is completed by holding at ℃ for 10 minutes. Next, mix the remaining water and all of the flour into the fermented liquid, and heat to about 30°C.
The mixture was held for about 50 minutes for primary fermentation. At this point, the volume has approximately tripled. Next, a super absorbent resin was mixed into this mixture and divided into three parts, and the mixture was held at about 40°C for about 50 minutes to undergo secondary fermentation. Each of the three divided kneaded products expanded approximately twice. After about 10 minutes of bench time, these were surrounded by rectangular parallelepiped blocks and heated at about 190 to 200° C. for about 10 minutes to bake them.

The bread baked according to the above procedure has an average pore diameter of about 0.7. ,, the average diameter of the pores in the center is about 1.5 mm.
The size of each block was a rectangular parallelepiped of approximately 80 x 160 x 70. When this was cut in the center and divided into two parts, and water was supplied from the center of the cut cross section, water penetrated quickly because the pore diameter in the center was large, and it penetrated in about 15 seconds, and the amount of water retained was 380 cc per half block. The volume of a half-flock of bread is about 448 cc, and the weight of the base material is about 58 g, so the water absorption efficiency is close to 100%. Also, the amount of water absorbed per gram of super absorbent resin is 1
It is 52cc. The flock of this bread was cut into two parts and then heated and vacuum-dried.

By applying a peeling material such as wax to the iron plate in front of the baked clay on the outside of this bread, it was possible to simultaneously create a waterproof film, and the entire half-flock of the bread could be used as a water-absorbing bag. The absorbed water turns into a gel, so even if the cut end was placed face down, no water would come out. Also, about 1 piece of this bread
It was also effective when cut into pieces with a thickness between 0 and 0,000 yen, and used as a loaf of bread on a table or as a substitute for disposable diapers.

Example 2 Raw materials for urethane foam were prepared in the following proportions.

Polyester ioo part tolylene diincyanate 36 parts activator
6 parts super absorbent resin powder 15 parts urethane The procedure for molding the foam was as follows.

First, the superabsorbent powder is well dispersed in tolylene diisocyanate by stirring (the polyester and activator are also well stirred and mixed).

Next, tolylene diisocyanate was added to this mixture while stirring, and foam molding was performed. The temperature is maintained around 25°C. The pore diameter of the urethane foam molded by the procedure described below was about 1.0 mm on average. The entire outer wall portion was cut to cut out blocks measuring 100 x 100 x 100. When city water was injected into this block, it held water at 880 (, (:).
Since there is 28g of at, the water absorption efficiency is 90.5%, and the amount of super absorbent resin powder contained in this block is approximately 4.5g.
Therefore, the amount of water absorbed per 1 g of powder was 195 cc, and the time required for water absorption was about 20 seconds. In this water-absorbing state, even if you squeeze the block, the water does not come out), or the whole block is very sticky, so it is better to wrap it in cloth, etc. for handling. I don't think a polymer bag is particularly necessary.In addition, if you squeeze the sponge when absorbing water, it can absorb 1000 (hereinafter -11) water. This is also to retain water.

The sponge obtained in this example is inexpensive to manufacture and is very convenient to use.

Applicant Seiji Shube

Claims (1)

[Scope of Claims] (1) Sponge-like water-absorbing body made of a porous substance with open cells inside and added with a highly absorbent resin (2) Scope of Claims in which the base material of the porous substance is grain flour such as wheat flour 1st
(3) The sponge-like water-absorbent body according to Claim 1, wherein the base material of the porous substance is a synthetic polymer such as urethane or a com. (4) The base material of the porous substance is a synthetic polymer such as urethane or com. (5) The sponge-like water-absorbent body according to claim 1, wherein the porous substance base material is an inorganic substance such as diatomaceous earth.